HR: 11:05h
AN: H12D-04    [Abstracts]
TI: Evaluation Of CO2 Injection Into Brine Formations Below Oil Reservoir
AU: * Han, W
EM: wshan@nmt.edu
AF: New Mexico Institute of Mining and Technology, 801 Leroy Place Socorro, NM 87801, Socorro, NM 87801, United States
AU: McPherson, B
EM: bjnmtech2@gmail.com
AF: University of Utah, 122 South Central Campus Dr., Salt Lake City, UT 84112-0561, United States
AB: Two models evaluating CO2 trapping mechanisms in the SACROC northern platform were developed using an upscaled geocellular model. The first model was designed for simulating CO2 trapping mechanisms in a reservoir saturated only with brine. The other model was designed for simulating CO2 trapping mechanisms in a reservoir saturated with both brine and oil. CO2 trapping mechanisms in the brine-only model showed distinctive stages of trapping; the major CO2 trapping mechanisms were hydrostratigrapic (mobile), residual, and solubility trapping during the 200 year simulation period. However, in the brine-plus-oil model, the trapping mechanisms did not vary distinctly over time. Both oil solubility trapping and hydrostratigraphic (mobile) trapping were dominant mechanisms for the entire simulation period. The contrast in CO2 trapping mechanisms in the two models is attributed to differences in thermophysical properties between oil and brine. Based on the two simulation models, injecting CO2 into the brine-plus-oil model reduces the amount of mobile CO2, which would otherwise likely migrate vertically to the top seal. Several advantages of CO2 injection into reservoirs saturated with both brine and oil include: (1) CO2 solubility in oil is significantly greater than CO2 solubility in brine. (2) CO2 does not tend to migrate vertically because oil density is similar to CO2 density, (3) CO2 mobility is reduced when more than two phases coexist, (4) although mobile CO2 may reach the top of the target formation, an oil reservoir is typically capped by a sealing layer, and (5) infrastructure for CO2 injection is already built. As suggested, injecting CO2 into oil reservoirs provides several advantages for minimizing potential CO2 vertical migration. However, oil reservoirs are typically limited with respect to CO2 storage capacity. Therefore, to obtain advantages in terms of CO2 storage capacity and protection from potential leakage, we propose CO2 injection into brine formations below oil reservoirs.
DE: 1805 Computational hydrology
DE: 1807 Climate impacts
DE: 1832 Groundwater transport
DE: 3610 Geochemical modeling (1009, 8410)
DE: 3611 Thermodynamics (0766, 1011, 8411)
SC: Hydrology [H]
MN: 2007 Fall Meeting